Went to hospital HELP

Courtney • Wife & mother! I love my husband and my two little girls and baby boy! May 15th, 2017 ( married the love of my life, the father of my girls and baby boy ❤️ ) 06/24/16 👧🏼 09/04/19 👧🏼

Ok I went to the hospital because I had hurt my back and went to check on the little bean in my belly. So anyways according to my app I’m 6 weeks, well here at the hospital it shows I’m 4 weeks. My levels are in the 4,000s, how am I 4 weeks, could I’ve ovulated late? And I had strong positive. They doc said they’ve could of just guessed as there machine ain’t as accurate as Obgyn. Help? And is 4,000 good in pregnancy?